Generally, air conditioning (HVAC) systems include such equipment as air handling units, air ducts and chilled water lines. Typically, these HVAC system components are insulated for both thermal and/or acoustic purposes. Conventional insulation used in HVAC systems typically includes a facing layer adhered to an insulation layer and is installed with the facing layer positioned away from the air duct or the cold water pipe, i.e., toward the space through which the component passes. This arrangement tends to reduce migration or diffusion of the moisture-laden air to the cool surfaces and thereby reduces the amount of condensate formed.
During periods of higher relative humidity and/or in instances in which the facing layer is damaged or incomplete, water vapor from the surrounding air may diffuse through the insulation and condense on surfaces that have temperatures below the dew point of the adjacent air. When such condensation occurs, the interface between the insulation and the cool surface will be wetted by the condensate.
The facing layer, or layers, are typically nonporous and act as a barrier between the insulation body and the external environment. However, over time, and especially if, as is often the case, the facing is damaged, water vapor will migrate to and condense on the cool surface. This condensate will accumulate and will enter the adjacent insulating material, thereby reducing its insulating efficiency. These problems can be exacerbated in vertical installations due to the tendency of the condensate to flow downwardly along or adjacent the vertical surfaces resulting in excessive accumulation in the lower portions of the vertical installations and/or in adjoining horizontal portions of the installation.
Previous attempts to address the problem of condensate formation and removal have utilized one or more wicking materials to collect the condensate at or near the cool surface and transport it through a layer of wicking material away from the cool surface to an exterior surface region. Once at or near the exterior of the insulation, the condensate within the wicking material layer can evaporate into the surrounding air. Although this approach works well for substantially horizontal applications, the condensate accumulation associated with components or installations incorporating significant vertical surfaces tends to result in accumulations of condensate in the lower portion of the vertical installation that reduce the effectiveness of such solutions.